Piston.



E. R. HEWITT.

PISTON.

APPLICATION FILED FEB.9, 1912.

1,1 15,535. Patented N0v.3, 1914.

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ring UNITED STATES PATENT OFFICE.

EDWARD R. HEWITT, 0F RINGWOOD, NEW JERSEY.

PISTON.

Application filed February 9, 1912. Serial No. 676,610.

To all whom it may concern: 4

Be it known that I, EDWARD R. HEWITT, a citizen of the United States, resident of Ringwood, in the county of Passaic, State of New Jersey, have invented certain new and useful Improvements in Pistons, of which. the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

This invention pertains to pistons, and more particularly such as are used in internal combustion engines, and has for its object features of construction of the piston to improve the operation and particularly certain conditions of 'ne. A

The application of my-invention may be on other forms of engines or under other conditions, and may be modified from what I hereafter specifically describe and show in the accompanying drawings in which a specific embodiment is illustrated.

The drawing shows an engine of simple construction in vertical sect-ion, showing the piston partly broken away. In the drawing, A is a cylinder; B a piston; C a crankcase; D piston packing rings; E iston oil-ring; F annular oil recess and E another annular oil recess; G indicates oil holes, G other oil holes in the piston.

In the usual four-cycle engine operation, the engine, as shown, is lubricated in the usual manner so that the walls of the cylinder A are covered with asuitable amount of oil. The reciprocating movement of the piston B causes the oil ring E to catch the oil on the down or out stroke of a suitable manner to aid the operation of the oiling ring E. The annular. groove F on the upper side of the oil ring E likewise gathelrisoil on the upper side of the oil In practice it has been found that under ordinary conditions on the suction stroke of an engine a considerable vacuum is formed at the head of the piston to draw in the gases. This vacuum is increased when the engine is throttled and amounts often to as much as 20 inches of mercury. The effect is carrying the vacuum down along the walls Specification of Letters Patent.

lubrication of the en- Patented Nov. 3, 191 4.

of the piston to the'rings which exerts a tension on the oil fil m at the joint between the engine and the cylinder wall. Such tension causes the oil to flow in the thin film past the'ring and to the head of the piston,

reaching the combustion chamber where it is carried away as smoke. On the other hand when the engine is working under full load, the suction is much reduced owing to the throttle, being opened, and the tension on the oil film therefore less. In order to make these conditions at the edge of the oil ring alike under all working conditions of the engine, I have placed the two oil grooves, one above and the other below the oil ring, both connected with the interior of the piston, which space is always subject to crankcase pressure conditions. Thus the conditions on the 'oil film are always the same no matter what conditions exist at the head of the piston. The eifect of my invention is the equalizing of the pressure at all times at both sides of theoil ring. To effect this a hole or a'number of holes, such as G, are bored from the annular groove F through the piston wall.

These-holes are made of such size and arrangement that they will permit the pressure existing in the crankcase and below the piston to communicate with the annular groove F in the same manner as it communicates with the annular groove F through the hole, or holes Gr. By the addition of the holes G, in conjunction with the holes G, equalizing of the pressure on both sides of the'oil ring E is established, and the oiling of the cylinder walls by means of'the oil ring E is consequently likewise subject to the pressure conditions in the crankcase. The effect is the maintaining on either side of the oil ring E the crankcase conditions as to pressure, and. this results in eliminating those troubles which have become evident and very objectionable where the provisions above described do not exist.

As the application of my invention may be varied and modified to suit constructions of engines and particular conditions, or in View of other requirements, I do not limit myself to the exact construction herein shown and described, but

What I claim and desire to secure by Letters Patent is:

1. In an internal combustion engine, in combination with a cylinder, piston andv crankcase cooperating .to vary the atmospheric pressure between the piston and the crankcase, a packing and oil ring on the piston, annular grooves above and below and contiguous to the main groove of said oil ring, a passage between the upper groove and the interior of the piston.

2. In combination, a piston for an internal combustion engine, packing rings, an oil ring at the inner end of said piston, an open groove on the inner side of and contiguous to said oil ring and a passage or vent between said groove and the inner side of the piston, a recess'in the outer surface of the piston between the oil ring and the head of the piston, and a passage or vent between said recess and the inner side of the iston.

3. In combination in a piston for lnternal. combustion engines, a packing ring, an oil ring, a groove in the surface of said piston between and extending from the oil ring and the inner end of the piston, and a groove between the oil ring and the head of the piston and contiguous to the oil ring groove, vents between each of said grooves and the interior of the piston whereby the pressure conditions in the crankcase are maintained in both of said grooves.

4. In a piston, a main packing ring groove and adjacent and contiguous thereto a second open groove of lesser depth than the main groove,

5. In a piston, a paclnng ring groove, open recesses laterally contlguous to said groove of lesser depth than the piston surface, for the purpose described.

6. In a piston, a groove, a secondary groove within the main groove, a packing ring in the secondary groove, whereby an open groove or recess is left between the edge of the packing ring and theedge of the main groove for the purpose described.

This specification signed and witnessed this 5th day of February 1912.

EDWARD R. HEWITT. 

